This invention relates to a process for producing metal clad reinforced resin laminates which desirably minimizes the variation in characteristics of the resultant clad laminates for use in the production of printed circuit wiring boards.
Various methods are known for producing rigid metal clad laminates. They may be classified into one of the following two types.
In the batchwise process, metal clad laminates are produced by impregnating a fibrous substrate with a resin varnish, drying the substrate to prepare a prepreg, stacking a plurality of prepregs to a desired thickness, bonding a cladding metal foil on one or both sides of the stack with adhesive coating being applied on the surface of metal foil, and finally curing the assemblage under heat and pressure in a molding press.
In the continuous mode process such as those disclosed in Japanese Unexamined Patent Publication No. 4838/1980 and Japanese Patent Application No. 1020/1980, both assigned to the same assignee as the present application, a plurality of continuous lengths of fibrous substrate are conveyed in a generally horizontal direction in parallel, impregnated with a curable liquid resin, and combined to form a unitary assemblage. A cladding metal foil is continuously applied on one or both sides of the assemblage and the resultant green clad laminate is cured by passing through a curing zone.
Experiments have shown that the performance of such metal clad laminates often varies to a relatively great extent from one to another regardless of the type of production method.
Therefore, it is a main object of the present invention to provide a process for producing metal clad laminates which may solve the abovementioned problem.